<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <title>Title</title>
</head>
<body>
<script>
    //1. 实现一个方法revertDomain，将域名倒置
    const revertDomain = (domainName) => domainName && domainName.split('.').reverse().join('.') || '您输入域名不正确'
    console.log(revertDomain('www.douyin.com'))
</script>
</body>
</html>
